Salomaa, Arto <br/><br/>
Automata - theoretic aspects of formal power series / 
by  Arto Salomaa and  Matri Soittola 
 -  Springer-Verlag,   1978. 
<br/><br/><label>Subjects--Index Terms: </label>Automatic Control Engineering 
<br/><br/><label>Dewey Class. No.: </label>629.891